Samsung Galaxy Tab or Lenovo Tab Pro - that's where I'd look in your price range. Both work great for drawing, the screens are bright and responsive, styluses come with them or cost less than for an iPad. They'll work fine for online classes too.
The main thing with Android here is apps. If your son already uses certain programs on his phone or computer, check if they're in the Play Market and how well they're optimized there. Krita works, Ibis Paint works, but sometimes they're a bit slower than on iPad. But Procreate and Adobe Fresco aren't available on Android at all - if that's a dealbreaker for you, then you'll have to look at iPad instead.
In my experience, kids adapt to any system pretty quickly. If your budget is 20-30k - that's enough to pick a good tablet with a quality screen, and it'll last you years. Don't overpay for the brand name if the features are the same. The main thing is test the stylus before you buy it - it feels different for everyone.